This invention relates to servo mechanisms, and more particularly, to servo mechanism for controlling the shifting of a transmission between a forward ratio and a reverse ratio.
The use of countershaft type transmissions as automatic shifting transmissions is increasing. Such transmissions, as is well known, are generally structurally similar to manually shifted transmissions wherein the synchronizer type clutches have been replaced with fluid operated type clutches. The one remaining mechanical clutch in these systems is generally utilized during forward or reverse operation to establish drive connection between the lowest forward ratio gear and the output shaft and the reverse ratio gear and its meshing idler. Also, these clutches are generally dog type or jaw clutches which do not incorporate a synchronizer. Therefore, it is somewhat important that the gears and the shaft be either rotating at the same speed or that both are stationary.